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    <title>Document</title>
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    <h2>作业</h2>
    <dl>
        <dt>必做</dt>
        <dl>打开自己手机，看看自己的手机计算器</dl>
        <dl>仿照手机计算器，使用eval计算结果。</dl>
        <dl>至少要求实现 + - * /混合运算。</dl>
    </dl>
    <script>
        let str = "8 + 7 * 2 - (3 + 5)";
        let obj = eval(str);
        console.log(obj);
    </script>


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